Navigation system monitor



FIG. 1 is a front, top, right side perspective view of my new design for a navigation system monitor;

FIG. 2 is a front elevation view of my new design for a navigation system monitor;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is a top plan view thereof;

FIG. 5 is a bottom plan view thereof;

FIG. 6 is a left side elevation view thereof; and,

FIG. 7 is a right side elevation view of my new design for a navigation system monitor. 

The ornamental design for navigation system monitor, as shown and described. 